A multi-beam antenna may be used to receive signals from a plurality of stationary satellites, such as communications satellites and broadcasting satellites. A multi-beam antenna uses a multi-beam antenna rotation apparatus for adjusting the antenna to predetermined elevational, azimuth and rotation angles. An example of such multi-beam antenna rotation apparatus is disclosed in, U.S. Pat. No. 6,445,361 which issued on Sep. 3, 2002.
The antenna rotation apparatus disclosed in U.S. Pat. No. 6,445,361 includes a dish bracket, an elevation bracket and azimuth clamp. The dish bracket is fixed to the back of the dish antenna. A plurality of spaced-apart arcuate slots are formed in the dish bracket, being arranged on an imaginary circle drawn on the dish bracket. The dish bracket is provided with a projection at the center of the imaginary circle, which projects in the direction away from the dish antenna. The elevation bracket has a pair of wings which are connected together by a bottom formed integral with the wings. A hole is formed in the bottom, into which the projection of the dish bracket is fitted. Thus, the elevation bracket is rotatable about the projection so that the rotation angle of the dish antenna with the dish bracket can be adjusted to a desired rotation angle. Tabs are formed in the respective wings and are provided with bolt holes. After the dish antenna is rotated to the desired rotation angle, bolts are inserted through the bolt holes and the slots in the dish bracket. The screw bolts have their heads located on the wing side, and the bolts are screwed into nuts on the dish bracket side, whereby the dish antenna can keep the adjusted rotation angle. (Although not shown or described in the U.S. patent, the nuts should be used on the bracket side in order to fasten the bolts.) Each wing is provided with an elevation adjusting mechanism. The azimuth clamp is disposed between the wings.
With the above-described arrangement of the rotation apparatus, in order to maintain the rotation angle, the bolts are inserted from the elevation bracket side to extend to the dish bracket side, and the bolts are screwed to the nuts on the dish antenna side of the dish-elevation bracket assembly. This makes it troublesome to manufacture the rotation apparatus. An object of the present invention is to provide a dish antenna rotation apparatus which can be manufactured easily.